This document discusses using mobile devices for teaching. It describes how presentation slides can be delivered to students via desktop computers or mobile devices. It also discusses using Twitter as a "backchannel" for students to discuss course content in real-time or after class. Concerns about using Twitter include ensuring discussions stay on topic. Classroom response systems that allow polling and surveys are also covered, along with examples of response systems like Poll Everywhere and Socrative. The document encourages trying activities where students evaluate response systems and create sample polls.